The prolific Clop ransomware group has exploited vulnerabilities in several companies' popular file transfer products, developed by US software company Cleo, to hack dozens of corporate victims it claims to have hacked in recent weeks. Announced the name.
In a post on a dark web leak site seen by TechCrunch, the Russian-linked Klopp Gang listed 59 organizations it claims were compromised by exploiting high-risk bugs in Cleo's software tools.
This flaw affects Cleo's LexiCom, VLTransfer, and Harmony products. Cleo first disclosed this vulnerability in an October 2024 security advisory before security researchers observed it being heavily exploited by hackers several months later in December. .
Klopp claimed in his post that he notified the compromised organizations, but that the victim organizations did not negotiate with the hackers. Clop has threatened to release the allegedly stolen data on January 18th unless the ransom demand is paid.
Enterprise file transfer tools are popular targets for ransomware hackers, especially Clop, as sensitive data is often stored on the system. In recent years, ransomware groups have previously taken credit for exploiting vulnerabilities in Progress Software's MOVEit Transfer product and later mass exploiting vulnerabilities in Fortra's GoAnywhere managed file transfer software.
Following the recent hacking incident, at least one company has confirmed a breach related to the attack on Clop's Cleo system.
German manufacturing giant Covestro told TechCrunch that it was contacted by Klopp and subsequently confirmed that the group had accessed certain data stores on its systems.
“We have confirmed that there has been unauthorized access to a logistics server in the United States used to exchange shipping information with our carriers,” Covestro spokesperson Przemysław Jedryszyk said in a statement. “In response, we have taken steps to ensure the integrity of our systems, increase security monitoring, and proactively notify our customers.
Jedrysik acknowledged that “the majority of the information contained on the server was not sensitive,” but declined to say what kind of data was accessed.
Other alleged victims TechCrunch spoke to dispute Kropp's claims, saying they were not compromised as part of the gang's latest major hacking campaign.
Emily Spencer, a spokeswoman for US car rental giant Hertz, said in a statement that the company was “aware” of Klopp's claims, but added: “At this time there is no evidence that Hertz data or Hertz systems were affected.” No,” he said.
“Out of an abundance of caution, we continue to actively monitor this issue with the support of our third-party cybersecurity partners,” Spencer added.
Christine Panayiotou, a spokeswoman for Australian logistics company Lynfox, which was listed on Klopp's leak site, said the company does not use the Cleo software and has “not experienced any cyber incidents involving its systems.” He disputed the gang's claims.
Panayotou did not respond to a question about whether Linfox's data was accessed due to a cyber incident involving a third party.
Spokespeople for Arrow Electronics and Western Alliance Bank also told TechCrunch that they found no evidence that their systems were compromised.
Klopp also listed software supply chain giant Blue Yonder, which was recently compromised. The company confirmed the ransomware attack in November, but has not updated its cybersecurity incident page since December 12th.
When last contacted by TechCrunch, Blue Yonder spokesperson Marina Renneke said on Dec. 26 that the company “uses Cleo to support and manage certain file transfers,” and that potential He acknowledged that he was investigating the access, but added that the company had “no reason to believe the information.” The Cleo vulnerability is related to a cybersecurity incident that occurred in November. ” In a communication this week, the company provided no evidence of this claim, nor did it provide any more recent comment.
None of the companies that responded to TechCrunch's questions would say whether they have logging or other technical means to detect data access or leaks.
TechCrunch has not yet received responses from other organizations listed on Clop's leak site. Clop claims to be adding more victims to its Dark Web leak site on January 21st.
It's still unclear how many companies were targeted, and Cleo itself is listed as a Clop victim, but did not respond to TechCrunch's questions.